This invention relates generally to the treatment of yarn in package form, and more particularly to a new method for treating yarn in package form with a yarn treating agent to modify the physical and/or chemical characteristics of the yarn comprising the steps of introducing the agent into selected portions of the outer surface of the package, and then infusing the agent into the package with a heated fluid applied under pressure. In one aspect of the present invention, the method involves treating yarn in package form with one or more dyes to create a repeating sequence of colors in a reproducible manner.
In another embodiment of the method of the invention, a dye acceptance modifier, e.g. a resist, is infused into one or both of the ends of a yarn package and a heated fluid, e.g. steam, is then introduced under pressure at a temperature and for a time sufficient to cause the dye acceptance modifier to partially penetrate the package and contact individual strands of yarn or fibers, and to set the dye acceptance modifier, if necessary. The yarn so treated may then be dyed directly by conventional techniques, or fashioned with other ends of treated or untreated yarns to form a fabric after which the fabric is dyed to provide a pleasing pattern of several tones or shades.
In another embodiment of the invention, a plurality of dyestuffs are introduced at the ends of the package, and a heated fluid, such as steam, is then introduced for a time sufficient to cause the dyes to at least partially penetrate the package.
In addition, the present invention contemplates an apparatus in which the aforementioned method may be practiced to treat yarn in package form either with dye acceptance modifiers, dyes, or other treating agents, to achieve desired characteristics.
In general, the pleasing color effects which can be obtained in a fabric through the use of what is commonly referred to as "space dyeing" have been recognized in the art. Furthermore, methods and apparatus have been developed over the years to achieve such effects by selectively dyeing portions of a yarn package. As used herein, the term, "yarn in package form", is intended to denote and mean a mass of yarn which is wound on a tube, cone, pern or other such conventional holders. These methods fall into two broad categories. One of these categories involves the use of needles to inject dye into selective portions of the yarn package. Typical of this type of treatment is the process disclosed in U.S. Pat. No. 3,547,575. Such prior art methods are time consuming and present problems with reproducibility and uniformity of dyeing. Furthermore, when using fine denier yarns, the needles usually tear the yarn fibers causing obvious problems when the yarn is subsequently fashioned into a fabric by weaving or knitting.
The second broad category of prior art processes is typified by U.S. Pat. No. 3,145,398 in which dye is forced radially through selective portions of a yarn package through the use of centrifugal force. The centrifugal force method exhibits the inherent disadvantage of distorting the yarn package during the process.
It is noted, in passing, that pressure per se has been used in the prior art for dyeing yarn in package form. However, in such prior art processes, as disclosed for example in U.S. Pat. Nos. 3,878,575 and 1,841,024, the entire package was uniformly dyed to the same shade or color.
Space dyeing has also been accomplished through the use of resists which alter dye sites in the yarn to cause them to be unreceptive to certain kinds of dyes. See, for example, U.S. Pat. No. 3,743,477 which discloses certain fiber-reactive compounds which may be applied to specified fibers to provide local reservation against dyeing with anionic or acid dyes. See also the application of resists by roller printing to form a pattern of resist and non-resist sections as disclosed in U.S. Pat. No. 3,700,402. However, roller printing fine denier yarns is both impractical and commercially unattractive because of the high cost.
In summary, each of the prior art methods of achieving a varigated dye effect on yarn has one or more undesirable characteristics which has heretofore limited the commercial acceptance of these methods. The need for a new technique which provides the desired pleasing multi-colored or ombre effect, without undesirable features, is evident.